How Are the Birds Doing?
Wrentit: stable
Wrentits remain relatively common at Palomarin, despite long-term habitat change and climate change.
Song Sparrow: declining
Song Sparrows were once one of the most common species at Palomarin, but their numbers have declined locally, thought to be a result of the long-term habitat change.
Nuttall's White-crowned Sparrow: declining
Nuttall's White-crowned Sparrows have declined dramatically as the local vegetation has shifted from open scrub and grassland to dense coastal scrub and Douglas fir forest.
Spotted Towhee: stable
Spotted Towhee populations remain relatively stable at Palomarin.
California Scrub-Jay: stable
California Scrub-Jays are infrequently caught in our mist-nets, in part because they are larger than most of the species we catch and are more easily able to get themselves out! Capture rates are low but steady.
Wilson's Warbler: mixed
Wilson's Warbler numbers have declined slightly in our forested mist-netting area, even though the number of nesting territories has increased in other parts of our study area.
Swainson's Thrush: mixed
Swainson's Thrush numbers have remained steady in our forested mist-netting area, even though the number of nesting territories has increased in other parts of our study area.
Fox Sparrow: stable
Fox Sparrows are relatively steady, except for an unusual spike in their numbers in 2013, possibly the result of an extremely productive nesting season in Alaska.
Golden-crowned Sparrow: declining
Golden-crowned Sparrows have been slowly declining, but with a bump in their numbers in 2013 similar to Fox Sparrow, possibly the result of an extremely productive nesting season in Alaska.
Hermit Thrush: declining
Hermit Thrushes have declined slightly over the years.
This question is frequently asked by those who care about birds — whether they are a scientist, a birder, or simply a nature lover — and answering it is the key first step to effective bird conservation. Operating year-round since 1966, the Palomarin Field Station provides a unique long-term perspective on West Coast bird populations.
Fewer birds at Palomarin
One way to measure the abundance of the local bird community is the number of birds captured as part of our long-term mist-netting and banding study. The bird community changes with the seasons as migrants come and go, so we examine total capture rates of individual birds during each season and overall in each year. Capture rates have declined overall, and especially during the fall season.
Select lines at top right to view capture rates by season.
Note: Annual totals are calculated March through February of the following calendar year, to keep an entire winter season together.
Why is tracking bird populations important for bird conservation?
Our declining capture rates mirror the continent-wide pattern of declining bird populations across North America, with an estimated 3 billion fewer birds since 1970. In particular, the decline in captures during the fall suggests a reduced number of migratory birds passing through Palomarin on fall migration. By examining long-term variation in capture rates, we can identify individual species that are declining rapidly and determine where and when conservation attention is needed. These declines likely reflect a combination of habitat loss and degradation along migration routes, the additional impacts of climate change on their ability to raise young and survive each year, and local habitat changes that might make Palomarin more or less suitable for individual species.
Although we study the entire community of birds at Palomarin, we pay particular attention to a suite of focal species to understand how they are doing and what is driving any changes over time. Select a species below to see how annual capture rates of our focal species are changing over time and what this means.
Year-Round Residents
Present at Palo all year, these bird species often maintain their territories even during the nonbreeding season. Changes in the capture rates of these species are most likely to reflect changes to the local habitat and climate. While most of these populations are relatively stable, we have seen declines in Nuttall’s White-crowned Sparrows and Song Sparrows, thought to be related to the local habitat changes.
Seasonal Migrants
Present at Palomarin only for part of the year, Neotropical migrants spend the spring and summer breeding season with us, then migrate to the tropics of Latin America to spend their winter. Changes in the capture rates of these species may reflect a combination of changes in habitat or climate in the tropics, along their migration routes, or local effects of changes at Palomarin.
For both of these species, trends in capture rates (from our forested mist-netting area) tell a different story than the growing number of nesting territories throughout other parts of the Palomarin study area, which are undergoing rapid habitat change.
Neotemperate migrants spend the summer as far north as Alaska, and then migrate to spend the winter with us. Changes in the capture rates of these species may reflect changes in habitat or climate in Alaska or Canada, along their migration routes, or local effects of changes at Palomarin.
Further research into the specific migration routes of our local populations of these species would provide additional insights into what is producing the patterns we see at Palomarin and how vulnerable these populations are to changes in habitat and climate.
How did we collect these data?
Since 1966, we have been mist-netting and banding birds at the Palomarin Field Station year-round. All of the birds we capture are carefully recorded and given uniquely-numbered bands provided by the U.S. Bird Banding Laboratory. All of these data are collected by staff, volunteers, and especially the hundreds of interns who have trained at Palomarin over the years.
For more information on how we carefully capture and band birds to collect this valuable data, please watch our video: Bird-banding and Mist-netting with Point Blue
Plan your visit!
Although the Palomarin Field Station is currently closed to the public, we welcome you to plan your visit in the near future. Visitors can drop in and join our intern and staff biologists to learn how we collect this valuable data on bird populations — and hopefully see a bird in the hand! More information on visiting and scheduling groups.